Scientists have proposed a new theory suggesting that lifeforms found in Venus’ clouds could be activating a chain of chemical reactions that makes the environment habitable.
This self-sustaining chain could explain many of the bizarre anomalies found in the planet’s upper atmospheric, which have puzzled scientists for decades.
A team of researchers at MIT, Cardiff University and Cambridge University have published the new hypothesis in Proceedings of the National Academy of Sciences.
Scientists have long been puzzled at the presence ammonia in Venus’ atmosphere. This gas was detected tentatively in 1970s. According to all accounts, it should not be manufactured through any chemical process.
The researchers created a series of chemical reactions to demonstrate that ammonia can be present in a gas.
This would then increase the pH of clouds from approximately -11 to 0. This would allow for a range of acidity within which life can live, even though it is still very acidic.
The team notes that lifeforms exist on Earth that can produce ammonia to make an otherwise acidic environment livable.
“We know that life is possible in acid environments on Earth. But nothing is as acidic as the Venusian clouds. However, if ammonia is being produced in the clouds, that will neutralize some of their droplets, making them potentially habitable,” Dr William Bains, co-author of this study, from Cardiff University’s School of Physics and Astronomy.
The authors suggest that ammonia is derived from biological sources, rather than non-biological sources like lightning or volcanic eruptions.
“Ammonia shouldn’t exist on Venus,” said Professor Sara Seager, co-author of the study, from MIT’s Department of Earth, Atmospheric and Planetary Sciences. It has hydrogen attached to its, and there is very little hydrogen around. Any gas that doesn’t belong in its environment is automatically suspicious.
The team discovered anomalies or chemical signatures in the clouds by combing data from previous missions.
Other than the presence of oxygen, certain non-spherical particle and some other anomalies, there were also unexpected levels of watervapor and sulfur dioxide.
The team investigated whether the anomalies could have been explained by dust. They argued that minerals, swept up from Venus and into the cloud, could interact to produce some, though not all, anomalies.
Although the chemistry was clear, the physical requirements were not possible. A large amount of dust would be needed to rise into the clouds in order to produce the anomalies.
The team wondered if the anomalies could have been explained by ammonia. They then set about modeling a series chemical processes in search for an answer.
They discovered that, if life produced ammonia, chemical reactions would naturally produce oxygen.
Once ammonia is present in the clouds, it will dissolve in droplets containing sulfuric acid. This neutralizes the acid and makes the droplets quite habitable.
The droplets would be transformed by the addition of ammonia to their liquid form. Once ammonia has been dissolved in sulfuric acids, the reaction would cause any surrounding sulfur dioxide to also dissolve.
The presence of ammonia could then explain most of the major anomalies in Venus’ cloud clouds. Researchers also found that meteorites, lightning, volcanic eruptions and even meteorites could not chemically produce enough ammonia to explain the anomalies.
Bains said that “there are many other obstacles for life to overcome” if one wants to live in Venus’ clouds. “There is almost zero water there, and all living things that we know require water. If there is life, then neutralizing acid will make the clouds a bit more habitable.
Scientists might have a chance to test for ammonia in the atmosphere of Venus with the Venus Life Finder Missions. These private-funded missions will send a spacecraft to the planet to measure the clouds for signs of life and ammonia.
Astrobiology
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